Wireless ic device

ABSTRACT

An article package formed from, for example, an aluminum-evaporated laminated film includes a cut-out section, which has no aluminum-evaporated layer, in an edge. An electromagnetic-coupling module is disposed in the cut-out section. A wireless IC device is constituted by the electromagnetic-coupling module and an aluminum-evaporated layer of the package. A magnetic-field antenna of the electromagnetic-coupling module is coupled to the aluminum-evaporated layer of the package. The whole of the article package acts as a radiator of the antenna.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wireless integrated circuit (IC)device applied to a radio-frequency identification (RFID) system thatperforms data communication in a non-contact manner usingelectromagnetic waves.

2. Description of the Related Art

In recent years, an RFID system that transmits information usingcontactless communication between a reader/writer generating inductionfields and a wireless IC device being attached on an article and storingpredetermined information has been being used as a merchandisemanagement system.

FIGS. 1A and 1B illustrate an example of a contactless IC tag (wirelessIC device) in which an IC tag label is attached to an IC tag antennadisclosed in Japanese Unexamined Patent Application Publication No.2003-243918. FIG. 1A is a plan view thereof, and FIG. 1B is an enlargedcross-sectional view taken along the line A-A in FIG. 1A. Thecontactless IC tag antenna is constituted by two pieces of separatedantenna patterns 91 and 92. The antenna patterns 91 and 92 are formedfrom a thin metal layer.

A label base 82 b of a contactless IC tag label 82 is provided withantennas 101 and 102 on which an IC chip 85 is implemented. The antennas101 and 102 of the contactless IC tag label 82 are attached to theantenna patterns 91 and 92 so as to be in contact therewith ananisotropic conductive adhesive 84 disposed therebetween, therebyforming a contactless IC tag 90.

A sealant film 83 is disposed on the surface of the label base 82 b toprevent the IC tag label from peeling off. In such a manner, a packagewith an IC tag, 81, is finally formed.

A contactless IC tag and a package with the tag attached described inJapanese Unexamined Patent Application Publication No. 2003-243918 havethe following problems.

(a) A step of forming an antenna is necessary because the antenna is notformed in the same step of forming a package. This leads to an increasein the duration of a manufacturing process and to an addition ofelements, thereby increasing the manufacturing cost of the package.

(b) It is necessary to have a large antenna pattern to obtain sufficientradiation characteristics, which means that an IC tag cannot be attachedon a small article.

(c) An IC tag is attached on the base of an article and is covered withanother film, thereby resulting in the thickness of the IC-tag formedportion being increased.

SUMMARY OF THE INVENTION

In order to overcome the problems described above, preferred embodimentsof the present invention provide a wireless IC device that solves theabove-described problems, reduces the cost of manufacturing a package,is attachable to a small article, and includes a tag formed portionhaving a reduced thickness.

According to various preferred embodiments of the present invention, awireless IC device is constructed as described below.

(1) The wireless IC device includes a high-frequency device and aradiation electrode. The high-frequency device is anelectromagnetic-coupling module or a wireless IC chip. Theelectromagnetic-coupling module includes a wireless IC chip and a feedercircuit board in electrical communication with the wireless IC chip. Thefeeder circuit board is coupled to an external circuit. The radiationelectrode is coupled to the high-frequency device mounted thereon. Theradiation electrode is part of an article and acts as a radiator.

(2) The radiation electrode may include a conductive portion having apredetermined area. The conductive portion may include a cut-out sectionlocated at an edge. The high-frequency device may be disposed in thecut-out section. The high-frequency device may be coupled to theconductive portion within the cut-out section.

(3) The radiation electrode may include a conductive portion having apredetermined area and having a non-conductive section as part thereof.The high-frequency device may be disposed in the non-conductive sectionand adjacent to an edge thereof. The high-frequency device may becoupled to the conductive portion located in the vicinity of thenon-conductive section.

(4) The wireless IC device may further include a loop electrode disposedin an implementation region for the high-frequency device (adjacent toan implementation field) such that a loop surface of the loop electrodeis oriented in an in-plane direction of the radiation electrode, theloop electrode being coupled to the high-frequency device and being indirect electrical communication with the radiation electrode.

(5) The wireless IC device may further include a loop electrode disposedin an implementation region for the high-frequency device (adjacent toan implementation field). The loop electrode may be coupled to thehigh-frequency device. The loop electrode may be electromagneticallycoupled to the radiation electrode with an insulating layer disposedtherebetween.

(6) The wireless IC device may further include a matching electrodedisposed between the implementation region for the high-frequency deviceand the loop electrode. The matching electrode may be configured toenable direct communication between the high-frequency device and theloop electrode.

(7) The wireless IC device may further include at least one of aresonant circuit and a matching circuit disposed in the feeder circuitboard.

(8) The radiation electrode may include, for example, a metallic layerof an article package in which a sheet containing a conductive layer isformed into a bag or pack.

(9) The radiation electrode may include, for example, an electrodepattern formed on a circuit board in an electronic apparatus.

(10) The radiation electrode may include a metallic plate disposed on aback surface of a component such as a liquid crystal panel in anelectronic apparatus.

According to various preferred embodiments of the present invention, thefollowing advantages can be obtained.

(1) It is unnecessary to have a step and an additional member forproducing an antenna pattern on an article, as required in the deviceillustrated in FIGS. 1A and 1B. Therefore, there is little increase incost caused by the provision of a wireless IC device to an article.

The whole or part of an article can be used as a radiator. Accordingly,sufficient radiation characteristics can be obtained even when the tagis attached on a small article.

The thickness of a region where the high-frequency device is mounted onthe base of an article can be reduced. Accordingly, protuberance of thehigh-frequency device can be suppressed and prevented, which means thatthe appearance of the article is not impaired.

In addition, the use of the electromagnetic coupling module enablesimpedance matching between the wireless IC chip and the radiationelectrode to be designed within the feeder circuit board. This obviatesthe necessity to limit the shape and material of the radiationelectrode, which means that any article can be supported.

(2) Arranging the high-frequency device in the cut-out section at anedge of the conductive portion which has a predetermined area andcoupling the high-frequency device to the conductive portion within thecut-out section of the conductive portion enables the high-frequencydevice to be disposed so as not to protrude from the outer shape of thearticle and also enables the conductive portion to be effectively usedas a radiator.

(3) Arranging the high-frequency device in the non-conductive sectioncontained in the conductive portion which has a predetermined area andcoupling the high-frequency device to the conductive portion being inthe vicinity of the non-conductive section enables the high-frequencydevice to be disposed so as not to protrude from the outer shape of thearticle and also enables the conductive portion to be effectively usedas a radiator.

(4) Providing the implementation region for the high-frequency devicewith the loop electrode being coupled to the high-frequency device andbeing in direct electrical communication with the radiation electrodesuch that the loop surface is orientated in the in-plane direction ofthe radiation electrode enables easy matching between the high-frequencydevice and the loop electrode, and strong coupling of the loop electrodeto the radiation electrode enables high gain.

(5) Providing the implementation region for the high-frequency devicewith the loop electrode being coupled to the high-frequency device andbeing electromagnetically coupled to the radiation electrode with theinsulating layer disposed therebetween enables the high-frequency deviceand the loop electrode to be matched easily, and the insulation betweenthe loop electrode and the radiation electrode in terms of directcurrent leads to improvement in resistance to static electricity.

(6) Providing the matching electrode in between the implementationregion for the high-frequency device and the loop electrode enables thematching electrode to be used as an inductor for impedance matchingbetween the radiation electrode and the high-frequency device. Thisincreases the flexibility in design of impedance matching, and thedesign can be facilitated.

(7) Providing the resonant circuit within the feeder circuit boardincreases frequency selectivity, thus enabling an operating frequency ofthe wireless IC device to be determined approximately by a self-resonantfrequency. Thus, energy of signals at a frequency for use in an RFIDsystem can be transmitted and received with a high degree of efficiency.In addition, the optimal resonant frequency can be set in considerationof the shape and size of the radiator, thus enabling improvement in theradiation characteristics of the wireless IC device.

Providing the matching circuit within the feeder circuit board enablestransmission and reception of energy of signals at a frequency for usein an RFID system with a high degree of efficiency.

(8) Using, as the radiation electrode, the metallic layer of an articlepackage in which a sheet containing a conductive layer is formed into abag or pack enables the article package containing the metallic layer tobe used without any special process. Almost all of the surface of thearticle package can act as a radiator, thus enabling the ID of eacharticle to be read even when multiple articles are piled up.

(9) Using an electrode pattern formed on a circuit board in anelectronic apparatus as the radiation electrode enables the circuitboard included in the electronic apparatus to be used without anyspecial process and facilitates implementation of the high-frequencydevice.

(10) Using a metallic plate disposed on the back surface of a componentsuch as a liquid crystal panel in an electronic apparatus as theradiation electrode enables the component in the electronic apparatuswithout any special process, which means that the size and cost are notincreased.

Other features, elements, characteristics and advantages of the presentinvention will become more apparent from the following detaileddescription of preferred embodiments of the present invention (withreference to the attached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate a known wireless IC device shown in JapaneseUnexamined Patent Application Publication No. 2003-243918.

FIG. 2 illustrates an article and a wireless IC device attached thereonaccording to a first preferred embodiment of the present invention.

FIGS. 3A and 3B illustrate the wireless IC device, showing onlycomponent parts of the article illustrated in FIG. 2.

FIG. 4 illustrates an article and a wireless IC device attached thereonaccording to a second preferred embodiment of the present invention.

FIG. 5 illustrates the wireless IC device, showing only component partsof the article illustrated in FIG. 3.

FIGS. 6A and 6B illustrate an article and a wireless IC device attachedthereon according to a third preferred embodiment according to thepresent invention.

FIG. 7 illustrates an article and a wireless IC device attached thereonaccording to a fourth preferred embodiment of the present invention.

FIGS. 8A and 8B illustrate a cross-sectional view taken along asubstantially center line that passes through a main portion of thewireless IC device and a partial enlarged plan view of the main portionof the wireless IC device, respectively.

FIGS. 9A and 9B illustrate a wireless IC device according to a fifthpreferred embodiment of the present invention.

FIG. 10 is an external perspective view of an electromagnetic-couplingmodule for use in a wireless IC device according to a sixth preferredembodiment of the present invention.

FIG. 11 is an exploded view that illustrates an internal structure of afeeder circuit board of the electromagnetic-coupling module.

FIG. 12 is an equivalent circuit diagram that includes the feedercircuit board and a cut-out section of a metallic layer.

FIG. 13 illustrates an article and a wireless IC device attached thereonaccording to a seventh preferred embodiment of the present invention.

FIG. 14 is a cross-sectional view of a main portion of the wireless ICdevice.

FIG. 15 is an exploded perspective view of a feeder circuit board of awireless IC device according to an eighth preferred embodiment of thepresent invention.

FIG. 16 is an equivalent circuit diagram of a main portion of thewireless IC device.

FIGS. 17A and 17B are perspective views of an electromagnetic-couplingmodule for use in a wireless IC device according to a ninth preferredembodiment of the present invention.

FIGS. 18A and 18B are perspective views of a mobile telephone terminalthat includes a wireless IC device according to a tenth preferredembodiment of the present invention and a cross-sectional view of a mainportion of an internal circuit board, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First PreferredEmbodiment

FIG. 2 is an external perspective view of an article and a wireless ICdevice attached thereon according to a first preferred embodiment of thepresent invention. An article 70 can be, for example, a bag of snackfood, such as potato chips. An article package 60 preferably is apackage in which an aluminum-evaporated laminated film is formed into abag.

The article package 60 has a cut-out section (a portion that is notcovered with an aluminum-evaporation film) 61 preferably located at anedge. An electromagnetic-coupling module 1 is disposed in the cut-outsection 61.

FIGS. 3A and 3B illustrate a structure of a wireless IC device, showingonly component parts of the article 70 illustrated in FIG. 2. In FIGS.3A and 3B, a radiation electrode 8 corresponds to an aluminum-evaporatedlayer of the aluminum-evaporated laminated film of the article package60. A loop electrode 7 is disposed within the cut-out section (a portionwhere the electrode is not formed) 61 of the radiation electrode 8. Theelectromagnetic-coupling module 1 is implemented so as to be coupled tothe loop electrode 7. The loop electrode 7 is patterned when aluminum isevaporated to form the aluminum-evaporated laminated film.Alternatively, the loop electrode 7 may be formed by producing aconductor pattern by printing in a step different from the aluminumevaporation.

FIG. 3B schematically illustrates an example of an electromagnetic-fielddistribution occurring in the radiation electrode 8 when the loopelectrode 7 acts as a transmitting antenna. In the drawing, the brokenlines represent loops of a magnetic field H, and the solid linesrepresent loops of an electric field E. The loop electrode 7 acts as amagnetic-field antenna. A magnetic field H generated by the loopelectrode 7 crosses the radiation electrode 8 at a substantially rightangle, thus inducing an electric field E. This electric-field loopinduces a magnetic-field loop, and they link together, thus expandingthe electromagnetic-field distribution.

In the foregoing example, the loop electrode 7 acts as a transmittingantenna. However, the loop electrode 7 can act as a receiving antenna.Also in this case, high gain can be obtained similarly because ofreversibility of an antenna.

When multiple articles are piled up, if each article includes aconductive portion having a predetermined area and acting as a radiationelectrode, as described above, the induced electromagnetic fields linktogether between the articles, thus expanding. Accordingly, even (orrather especially) when multiple articles are piled up, the wireless ICdevices can operate as a high-gain device. For example, when an antennaof a reader/writer is positioned in close vicinity to part of a pile ofbags of potato chips, the IDs of all of the pile of bags of potato chipscan be read.

The electromagnetic-coupling module 1 illustrated in FIGS. 3A and 3B caninclude a wireless IC chip and a feeder circuit board, which will bedescribed below. In the case where the feeder circuit board is used, twoelectrodes of the feeder circuit board are electromagnetically coupledto both terminals of the loop electrode 7. The electromagnetic-couplingmodule 1 can be replaced by a single wireless IC chip. In this case, twoelectrodes of the wireless IC chip are directly connected to bothterminals of the loop electrode 7. In either of these two cases, theloop electrode 7 is separated from the radiation electrode 8 in terms ofdirect current, so it is advantageous that the wireless IC device hashigh resistance to static electricity.

The loop electrode 7 has any shape as long as the loop electrode 7 isdisposed so as to couple input and output terminals of theelectromagnetic-coupling module 1 together.

Second Preferred Embodiment

FIG. 4 is an external perspective view of an article and a wireless ICdevice attached thereon according to a second preferred embodiment. Anarticle 71 can be, for example, a bag of snack food. An article package60 preferably is a package in which an aluminum-evaporated laminatedfilm is formed into a bag.

In an example illustrated in FIG. 2, the electromagnetic-coupling moduleis arranged in an edge of the article package. In an example illustratedin FIG. 4, an electromagnetic-coupling module 1 is disposed inside thearticle package 60 and away from the edge of the article package 60. Thearticle package 60 is formed from an aluminum-evaporated laminated filmhaving a non-conductive section 62 as part thereof. The non-conductivesection 62 is not covered with an aluminum-evaporated film. Theelectromagnetic-coupling module 1 is arranged within the non-conductivesection 62 and positioned adjacent to an edge thereof.

FIG. 5 illustrates a structure of an implementation region for theelectromagnetic-coupling module 1 illustrated in FIG. 4. In FIG. 5, thestructure of a loop electrode 7 and that of the electromagnetic-couplingmodule 1 are substantially the same as those in the first preferredembodiment illustrated in FIGS. 3A and 3B. A radiation electrode 8corresponds to an aluminum-evaporated layer of the aluminum-evaporatedlaminated film of the article package 60. The loop electrode 7 and theelectromagnetic-coupling module 1 are arranged within the non-conductivesection 62 such that the loop electrode 7 is adjacent to three sides ofthe radiation electrode 8.

The loop electrode 7 acts as a magnetic-field antenna and is coupled tothe radiation electrode 8. The radiation electrode 8 thus acts as aradiator of the antenna by substantially the same action in FIGS. 3A and3B.

If the loop electrode 7 and the electromagnetic-coupling module 1 aredisposed within the non-conductive section 62 having substantially thesame size as that of the area occupied by the loop electrode 7 and theelectromagnetic-coupling module 1, the magnetic field of the loopelectrode 7 is coupled to the radiation electrode 8 at the four sides,and the electromagnetic field induced in the radiation electrode 8 iscancelled, thus resulting in a gain reduction. To avoid this, it isimportant that the size of the non-conductive section 62 is sufficientlylarger than that of the area occupied by the loop electrode 7 and theelectromagnetic-coupling module 1 and one, two, or three sides of theloop electrode 7 are adjacent to the radiation electrode 8.

Third Preferred Embodiment

FIG. 6B illustrates a structure of a main portion of a wireless ICdevice according to a third preferred embodiment. FIG. 6A is an externalview of an article on which the wireless IC device is attached. In FIG.6A, an article 72 includes a substantially planar metallic body 63 and awireless-IC-device main portion 6 attached thereon. The substantiallyplanar metallic body 63 is a plate-shaped or sheet-shaped article havinga metallic layer contained therein or a metallic plate itself.

The wireless-IC-device main portion 6 is shaped like a tab index, asillustrated in FIG. 6B, and includes an insulating sheet 64. Theinsulating sheet 64 includes an adhesive layer on the inside surface andsandwiches a loop electrode 7 and an electromagnetic-coupling module 1.The structure of the loop electrode 7 and that of theelectromagnetic-coupling module 1 are substantially the same as thoseillustrated in FIGS. 3A and 3B.

The wireless-IC-device main portion 6 is attached on the substantiallyplanar metallic body 63 illustrated in FIG. 6A such that the loopelectrode 7 is adjacent to an edge of the substantially planar metallicbody 63, as in the case of attaching a tab index.

Even when the conductive portion has no cut-out section in its edge, asdescribed above, disposing the loop electrode 7 of thewireless-IC-device main portion 6 adjacent to the edge of thesubstantially planar metallic body 63 enables the loop electrode 7 andthe substantially planar metallic body 63 (a conductive portion actingas a radiation electrode) to be coupled together and the substantiallyplanar metallic body 63 to act as a radiator of the antenna.

Fourth Preferred Embodiment

A wireless IC device according to a fourth preferred embodiment will nowbe described with reference to FIGS. 7 and 8A and 8B. The wireless ICdevice according to the fourth preferred embodiment preferably isapplied to a recording medium that has a metallic film, such as adigital versatile disc (DVD).

FIG. 7 is a plan view of a DVD. FIG. 8A is a cross-sectional view takenalong a substantially center line that passes through a region where awireless-IC-device main portion 6 is formed. FIG. 8B is a partialenlarged plan view of the wireless-IC-device main portion 6. In across-sectional view illustrated in FIG. 8A, the dimension of thethickness direction is exaggerated for purposes of illustration.

As illustrated in FIGS. 7 and 8A, a DVD 73 includes two disc-shapedelements bonded together. One of these elements includes a metallic film65. The wireless-IC-device main portion 6 is disposed at a portion of aninner edge of the metallic film 65.

As illustrated in FIG. 8B, a C-shaped cut-out section 66 is disposed ata portion of the inner edge of the metallic film 65. The cut-out section66 is a cut-out section of the metallic film pattern, not of the disc.The electromagnetic-coupling module 1 is arranged such that twoterminals thereof face two opposing tips defined by the cut-out section66. The inner edge surrounding the C-shaped cut-out section 66(indicated by the arrows in FIG. 8B) acts as a loop electrode.

Fifth Preferred Embodiment

FIGS. 9A and 9B illustrate structures of two wireless IC devicesaccording to a fifth preferred embodiment, respectively. Each of thewireless IC devices according to the fifth preferred embodiment includesa matching electrode disposed between an implementation region for ahigh-frequency device and a loop electrode, the matching electrodeenabling direct communication between the high-frequency device and theloop electrode.

In FIG. 9A, a metallic film 65 has the shape of a sheet or a plate andacts as a radiation electrode. The metallic film 65 has a cut-outsection 66 as part thereof, thus causing a region extending so as tosurround the inner edge of the cut-out section 66 to act as a loopelectrode.

A meandering matching electrode 67 and metallic-film end sections 65 aand 65 b being an implementation region for a high-frequency device(electromagnetic-coupling module or wireless IC chip) are formed withinthe cut-out section 66.

The provision of a matching circuit realized by the matching electrode67 allows a wireless IC chip to be directly implemented on themetallic-film end sections 65 a and 65 b.

In FIG. 9B, a radiation electrode 8 includes a non-conductive section62. The matching electrode 67, a loop electrode 7, and anelectromagnetic-coupling module 1 are arranged within the non-conductivesection 62 such that the loop electrode 7 is adjacent to three sides ofthe radiation electrode 8. The structure of the matching electrode 67and that of the implementation for the electromagnetic-coupling module 1preferably are substantially the same as those in FIG. 9A.

The loop electrode 7 acts as a magnetic-field antenna and is coupled tothe radiation electrode 8. The radiation electrode 8 thus acts as aradiator of the antenna by substantially the same action in FIGS. 3A and3B.

Each of the metallic film 65 illustrated in FIG. 9A and the radiationelectrode 8 illustrated in FIG. 9B may be a solid electrode on a circuitboard within, for example, a mobile telephone terminal.

Sixth Preferred Embodiment

FIG. 10 is an external perspective view of an electromagnetic-couplingmodule 1 for use in a wireless IC device according to a sixth preferredembodiment. This electromagnetic-coupling module 1 is applicable to awireless IC device according to other preferred embodiments. Theelectromagnetic-coupling module 1 includes a wireless IC chip 5 and afeeder circuit board 4. The feeder circuit board 4 performs impedancematching between a metallic film 65 acting as a radiation electrode andthe wireless IC chip 5 and also acts as a resonant circuit.

FIG. 11 is an exploded view that illustrates an internal structure ofthe feeder circuit board 4. The feeder circuit board 4 is a multilayerboard that includes a plurality of dielectric layers, each having anelectrode pattern formed thereon. An uppermost dielectric layer 41Aincludes lands 35 a to 35 d for implementation of a wireless IC chip. Adielectric layer 41B includes a capacitor electrode 51 in electricalcommunication with the wireless IC chip implementation land 35 b. Adielectric layer 41C includes a capacitor electrode 53. A capacitor C1is formed between the capacitor electrodes 51 and 53. Each of dielectriclayers 41D to 41H includes inductor electrodes 45 a and 45 b. Theseinductor electrodes 45 a and 45 b formed over the plurality of layersconstitute inductors L1 and L2. The inductors L1 and L2 preferably havea double-spiral shape and are inductively coupled to each otherstrongly. The dielectric layer 41F includes a capacitor electrode 54 inelectrical communication with the inductor L1. The dielectric layer 41Hincludes a capacitor electrode 55 in electrical communication with thecapacitor electrode 53. The capacitor electrode 54 forms a capacitorbetween the two capacitor electrodes 53 and 55. The electrodes of thedielectric layers electrically communicate with each other through viaholes 42 a to 42 i.

The capacitor electrode 55 faces the metallic-film end section 65 bdefined by the cut-out section of the metallic film 65 illustrated inFIG. 8 and constitutes a capacitor therebetween. The inductor electrodes45 a and 45 b are electromagnetically coupled to the metallic-film endsection 65 a, which face the inductor electrodes 45 a and 45 b.

FIG. 12 is an equivalent circuit diagram that includes the feedercircuit board and the cut-out section of the metallic layer illustratedin FIG. 11. In FIG. 12, the capacitor C1 corresponds to a capacitordefined between the capacitor electrodes 51 and 53 illustrated in FIG.11. A capacitor Cf corresponds to a capacitor defined between thecapacitor electrode 54 and the capacitor electrodes 53 and 55illustrated in FIG. 11. The inductors L1 and L2 preferably are definedby the inductor electrodes 45 a and 45 b illustrated in FIG. 11. Themetallic film 65 illustrated in FIG. 12 is a loop extending so as tosurround the inner edge of the cut-out section 66 illustrated in FIG. 8.The capacitor electrode 55 is capacitively coupled to the end section 65b, and the other end section 65 a is electromagnetically coupled to theinductors L1 and L2. Therefore, the loop extending so as to surround theinner edge of the cut-out section 66 acts as a loop electrode.

In the fourth preferred embodiment, the loop extending so as to surroundthe inner edge of the cut-out section of the metallic film acts as aloop electrode. However, the loop electrode may be formed within thecut-out section, as illustrated in, for example, FIGS. 3A and 3B, andthe electromagnetic-coupling module 1 constituted by the wireless ICchip 5 and the feeder circuit board 4 is implemented to the loopelectrode. In this case, the loop electrode is coupled to the metallicfilm 65, and the metallic film 65 acts as a radiator.

In the feeder circuit board 4, a resonance frequency is determined in aresonant circuit constituted by the inductors L1 and L2 and its straycapacitance. The frequency of a signal transmitted from the radiationelectrode is substantially determined by the self-resonant frequency ofthe resonant circuit.

The electromagnetic-coupling module 1 constituted by the feeder circuitboard 4 and the wireless IC chip 5 mounted thereon receives ahigh-frequency signal (for example, in the ultra-high-frequency (UHF)band) transmitted from a reader/writer (not shown) via the radiationelectrode, resonates the resonant circuit in the feeder circuit board 4,and supplies only a reception signal in a desired frequency band to thewireless IC chip 5. Then, a predetermined energy is extracted from thereception signal. By use of this energy as a driving source, informationstored in the wireless IC chip 5 is matched to a predetermined frequencyby the resonant circuit, and the information is then transmitted to theradiation electrode. The information is transmitted (transferred) fromthe radiation electrode to the reader/writer.

As described above, providing the resonant circuit within the feedercircuit board increases frequency selectivity, thus enabling theoperating frequency of the wireless IC device to be determinedapproximately by the self-resonant frequency. Thus, energy of signals ata frequency for use in an RFID system can be transmitted and receivedwith a high degree of efficiency. In addition, the optimal resonantfrequency can be set in consideration of the shape and size of theradiator, thus enabling improvement in the radiation characteristics ofthe wireless IC device.

Providing the matching circuit within the feeder circuit board enablestransmission and reception of energy of signals at a frequency for usein an RFID system with a high degree of efficiency.

Seventh Preferred Embodiment

FIG. 13 is a perspective view that illustrates a structure of a mainportion of a wireless IC device according to a seventh preferredembodiment. FIG. 14 is a partial enlarged cross-sectional view thereof.

In FIG. 13, a base 10 is a base of an article for mounting the wirelessIC device and can be, for example, an aluminum-evaporated laminatedfilm. A loop electrode 30 is formed on an aluminum-evaporated layer ofthe base 10. The loop electrode 30 has an opening at a predeterminedposition corresponding to a cut-out section described in the firstpreferred embodiment or a non-conductive section described in the secondpreferred embodiment and includes two ends 30 a and 30 b formed by theopening. An inductor electrode 20 and a capacitor electrode 25 aredisposed on the ends 30 a and 30 b, respectively, with an insulatinglayer arranged therebetween. The inductor electrode 20 has a spiralshape and, as described below, its inner edge is connected to thecapacitor electrode 25.

As illustrated in an enlarged view in FIG. 13, a wireless IC chip 5 ismounted on an end of the inductor electrode 20 and an end of thecapacitor electrode 25. More specifically, a wireless IC chipimplementation land 35 a is disposed on the end of the inductorelectrode 20, and a wireless IC chip implementation land 35 b isdisposed on the end of the capacitor electrode 25. In addition, wirelessIC chip implementation lands 35 c and 35 d are formed, thereby mountingthe wireless IC chip 5.

FIG. 14 is a cross-sectional view taken along the line II-II in FIG. 13.As illustrated in FIG. 14, the inductor electrode 20 faces the end 30 aof the loop electrode 30. The inner edge of the inductor electrode 20and the capacitor electrode 25 illustrated in FIG. 13 are connected witha wire 21.

As described above, a capacitor and an inductor for impedance matchingand adjustment of a resonant frequency can be disposed on the base 10 ofthe article, and the wireless IC chip 5 can be directly implementedthereon.

Eighth Preferred Embodiment

FIG. 15 is an exploded perspective view of a feeder circuit board 40 ofa wireless IC device according to an eighth preferred embodiment. FIG.16 is an equivalent circuit diagram thereof.

The feeder circuit board 40 is a multilayer board that includes aplurality of dielectric layers, each having an electrode pattern formedthereon. An uppermost dielectric layer 41A includes lands 35 a to 35 dfor implementation of a wireless IC chip. A dielectric layer 41Bincludes a capacitor electrode 51 in electrical communication with thewireless IC chip implementation land 35 b. A dielectric layer 41Cincludes a capacitor electrode 53. A capacitor C1 is formed between thecapacitor electrodes 51 and 53. Each of dielectric layers 41D to 41Hincludes inductor electrodes 45 a and 45 b. These inductor electrodes 45a and 45 b formed over the plurality of layers constitute an inductor L1having a double-spiral shape. The dielectric layer 41F includes acapacitor electrode 54 in electrical communication with the inductor L1.The dielectric layer 41H includes a capacitor electrode 55 in electricalcommunication with the capacitor electrode 53. The capacitor electrode54 forms a capacitor between the two capacitor electrodes 53 and 55(56).

A dielectric layer 41I includes capacitor electrodes 56 and 57. Thecapacitor electrode 56 electrically communicates with the capacitorelectrodes 53 and 55. The capacitor electrode 57 is electromagneticallycoupled to the inductor electrodes 45 a and 45 b.

Each of dielectric layers 41J to 41M includes an inductor electrode 46,and a dielectric layer 41N includes an inductor electrode 47. Theinductor electrodes 46 and 47 constitute a loop electrode L2 having anumber of turns of wire. The electrodes of the dielectric layerselectrically communicate with each other through via holes 42 a to 42 m.

That is, the feeder circuit board 40 is the one in which a loopelectrode is added to the feeder circuit board 4 illustrated in FIG. 11.As a result, a wireless IC device is constructed merely by mounting, onan article, an electromagnetic-coupling module formed by implementing awireless IC chip to the feeder circuit board 40, thus obviating thenecessity to provide the article with the loop electrode.

In FIG. 16, the capacitor C1 corresponds to a capacitor defined betweenthe capacitor electrodes 51 and 53 illustrated in FIG. 15. A capacitorCf corresponds to a capacitor defined between the capacitor electrode 54and the capacitor electrodes 53 and 55 illustrated in FIG. 15. Theinductors L1 a and L1 b are formed by the inductor electrodes 45 a and45 b illustrated in FIG. 15, respectively. The inductor L2 is preferablydefined by the inductor electrodes 46 and 47 illustrated in FIG. 15.

Ninth Preferred Embodiment

FIGS. 17A and 17B are plan views of electromagnetic-coupling modules 2and 3, respectively, for use in a wireless IC device according to aninth preferred embodiment. In an example illustrated in FIG. 17A, aloop electrode 12 and a wireless IC chip implementation land are formedon a substrate 11 as an electrode pattern, and a wireless IC chip 5 isimplemented thereon.

In an example illustrated in FIG. 15, in addition to a loop electrode, acapacitor and an inductor for impedance matching and adjustment of aresonant frequency are provided on a feeder circuit board. In contrast,in an example illustrated in FIGS. 17A and 17B, basically, a loopelectrode is integral with a wireless IC chip.

In an example illustrated in FIG. 17B, a spiral electrode pattern isformed on each of upper and lower surfaces of the substrate 11. Acapacitor electrode sandwiching the substrate 11 is arranged in asubstantially central region of the spiral electrode pattern. The lineson the upper and lower surfaces are connected together through thecapacitor. That is, the pass length and inductance are gained within alimited area by use of both surfaces of the substrate 11, thus formingthe loop electrode 12.

Either of the two electromagnetic-coupling modules 2 and 3 illustratedin FIGS. 17A and 17B are adjacent to a metallic film or metallic plate,acting as a radiation electrode, of an article such that the radiationelectrode and the loop electrode 12 are capacitively coupled to eachother. As a result, the metallic film or metallic plate of the articlecan be used as a radiator of an antenna without having to provide anarticle with a special circuit, as in the case of the first and secondpreferred embodiments.

Tenth Preferred Embodiment

FIG. 18A is a perspective view of a mobile telephone terminal thatincorporates a wireless IC device. FIG. 18B is a cross-sectional view ofa main portion of an internal circuit board. In addition to electroniccomponents 17 and 18, a feeder circuit board 4 on which a wireless ICchip 5 is mounted is implemented on a circuit board 15 within the mobiletelephone terminal. An electrode pattern 16 extends over a predeterminedarea on the upper surface of the circuit board 15. The electrode pattern16 is coupled to the wireless IC chip 5 with the feeder circuit board 4disposed therebetween and acts as a radiation electrode.

Another example is a wireless IC device mounted on a metallic panel onthe back of a liquid crystal panel within the mobile telephone terminalillustrated in FIG. 18A. That is, a wireless IC device illustrated inthe first to ninth preferred embodiments applied to the metallic panelcan be made to act as a radiator of an antenna.

The wireless IC device is applicable to an article that includes aconductive portion having a predetermined area, in addition to thearticles described in the preferred embodiments described above. Forexample, it is applicable to a medicine or snack food packaged in acomposite film containing aluminum foil, such as a press through package(PTP).

While preferred embodiments of the invention have been described above,it is to be understood that variations and modifications will beapparent to those skilled in the art without departing the scope andspirit of the invention. The scope of the invention, therefore, is to bedetermined solely by the following claims.

1. A wireless integrated circuit device comprising: a high-frequencydevice including a wireless integrated circuit chip and a feeder circuitboard in electrical communication with the wireless integrated circuitchip, the feeder circuit board being coupled to an external circuit; anda radiation electrode coupled to the high-frequency device mountedthereon, the radiation electrode being part of an article and acting asa radiator.
 2. The wireless integrated circuit device according to claim1, wherein the high-frequency device is an electromagnetic-couplingmodule or a wireless integrated circuit chip.
 3. The wireless integratedcircuit device according to claim 1, wherein the radiation electrodeincludes a conductive portion having a predetermined area, theconductive portion includes a cut-out section at an edge, thehigh-frequency device is disposed in the cut-out section, and thehigh-frequency device is coupled to the conductive portion within thecut-out section.
 4. The wireless integrated circuit device according toclaim 1, wherein the radiation electrode includes a conductive portionhaving a predetermined area and having a non-conductive section, thehigh-frequency device is disposed at an edge in the non-conductivesection, and the high-frequency device is coupled to the conductiveportion being in the vicinity of the non-conductive section.
 5. Thewireless integrated circuit device according to claim 1, furthercomprising a loop electrode disposed in an implementation region for thehigh-frequency device such that a loop surface of the loop electrode isoriented in an in-plane direction of the radiation electrode, the loopelectrode being coupled to the high-frequency device and being in directelectrical communication with the radiation electrode.
 6. The wirelessintegrated circuit device according to claim 1, further comprising aloop electrode disposed in an implementation region for thehigh-frequency device, the loop electrode being coupled to thehigh-frequency device, the loop electrode being electromagneticallycoupled to the radiation electrode with an insulating layer disposedtherebetween.
 7. The wireless integrated circuit device according toclaim 5, further comprising a matching electrode disposed between theimplementation region for the high-frequency device and the loopelectrode, the matching electrode being configured to enable directcommunication between the high-frequency device and the loop electrode.8. The wireless integrated circuit device according to claim 6, furthercomprising a matching electrode disposed between the implementationregion for the high-frequency device and the loop electrode, thematching electrode being configured to enable direct communicationbetween the high-frequency device and the loop electrode.
 9. Thewireless integrated circuit device according to claim 1, furthercomprising at least one of a resonant circuit and a matching circuitdisposed in the feeder circuit board.
 10. The wireless integratedcircuit device according to claim 1, wherein the radiation electrodecomprises a metallic layer of an article package in which a sheetcontaining a conductive layer is formed into a bag or a pack.
 11. Thewireless integrated circuit device according to claim 1, wherein theradiation electrode comprises an electrode pattern disposed on a circuitboard in an electronic apparatus.
 12. The wireless integrated circuitdevice according to claim 1, wherein the radiation electrode comprises ametallic plate disposed on a back surface of a component in anelectronic apparatus.